Compressible and expandable blade for a fluid pump

ABSTRACT

The invention relates to a compressible and expandable blade for the rotor of a fluid pump having at least two lamellae which are disposed adjacently, are pivotable respectively relative to an axis of rotation of the rotor and moveable relative to each other, and abut against each other in the expanded state of the blade such that they form together a continuous blade surface.

The present invention resides in the field of mechanics or micromechanics and can be applied advantageously in particular in medical technology.

The invention relates to a blade for a pump and the design thereof. Of concern thereby is a pump having a rotor, the rotor being compressible and expandable in order to be able possibly to change the overall dimensions of the pump. In this way, the pump can be pushed through not readily accessible openings or into narrow pipe systems, for which purpose it is firstly compressed and, after it has been moved to the location of use, is expanded again.

Such a pump can be used particularly advantageously in medical technology in the field of heart pumps or other pumps for body fluids which are normally used with catheters.

In the technical medical field, different types of micropumps are known, which pumps can be introduced in the compressed state with a catheter through a naturally occurring body vessel into the body of a patient and can be expanded in situ. In order to produce a corresponding radial compressibility and expandability, various effects can be used in the construction and the structure of the pump housing and the pump rotor, such as e.g. the use of so-called memory alloys which change their shape as a function of the ambient temperature or control the pump diameter specifically by providing specific transmission mechanisms which allow it.

A solution is known from DE 10 2004 054 714 A1 in which both the impeller of a micropump and the housing thereof is manipulated by a mutual axial displacement of the pump drive shaft in relation to a catheter. As a result, the housing is changed between a compressed and an expanded state.

A system is known from the patent document WO 00/2003103745 A2, in which the pump housing is likewise expanded mutually radially by an axial relative movement of two components.

A rotor is known from the US patent specification U.S. Pat. No. 7,393,181, the blade of which can be subdivided into a plurality of partial blades or rows of partial blades for improved compressibility/collapsibility. As a result of the subdivision, the individual partial blades are smaller than a one-part blade and almost flat so that they can be rolled in easily. However, the ability to be subdivided is restricted by the intrinsic stability of the partial blades which requires to be ensured.

With the background of the state of the art, the object underlying the present invention is to produce a rotor which can be produced as simply and economically as possible or a blade for such a rotor, high compressibility being paramount with as little as possible of a force expenditure so that, in order to withdraw the pump from the vessel, the compression of the pump rotor can be achieved without major external resistances. In addition, the corresponding pump is intended to be designed to be efficient and low-consumption.

The object is achieved according to the invention by the features of patent claim 1.

The invention provides a blade having a plurality of lamellae which are disposed adjacently, are moveable relative to each other and pivotable relative to an axis of rotation of the rotor, the lamellae abutting against each other in the expanded state of the blade such that they form together a continuous blade surface.

Due to their pivotability, lamellae of this type can be pivoted individually very easily into a space-saving state and, in the pivoted-out, expanded state of the blade or of the rotor, form a closed blade surface which is designed such that it fulfils the required technical flow conditions with respect to shape and surface design.

Relative to a collapsible membrane, the blade consisting of individual lamellae has the advantage that its components can, both in the compressed and in the expanded state, assume a defined shape and arrangement. The individual lamellae can respectively be mounted rotatably on the shaft of the rotor and in fact advantageously pivotable in a plane which includes the longitudinal axis of the rotor shaft or an axis parallel to such a shaft, the mounting points being able to extend around the rotor shaft in a spiral in order to produce a spiral blade in the unfolded state. However, also other types of mounting are conceivable, in which the lamellae are mounted for example on one or more webs or transverse spars which are connected, for their part, to the rotor shaft.

The individual lamellae can be of equal length but can also be designed to be of different lengths according to which final shape the blade is intended to assume. The pivotability of the individual lamellae is restricted so that these, in the opened state, can withstand the flow counterpressure of a fluid to be conveyed. However, the lamellae can also be mutually supported in that they abut against each other and possibly engage in each other forming a lock. For example, the lamellae can be designed in the manner of the elements of a bird feather, the quill of the feather corresponding comparatively to the rotor shaft.

The construction of the blade can be designed such that the blade expands during rotation in the operating direction due to the fluid counterpressure and, when rotating in the opposite direction, is compressed by the effect of the medium in which the blade moves. This makes the compression- and expansion movement particularly simple without greater forces requiring to be overcome. During application in the medical field, such a pump can hence be removed again in a simple manner and without the danger of damaging body vessels.

A particular embodiment of the invention provides that at least two lamellae, in particular each of the lamellae, have per se a dimensionally stable, in particular rigid configuration.

The blade obtains its flexibility not from the flexibility of a membrane but from the movability of the individual lamellae relative to each other. For this purpose, the lamellae must not exceed a specific width. Advantageously, the blade for example can consist of at least 10 or at least 50 lamellae. Such a blade can have in total a very small constructional size in order to be inserted into a blood vessel, for example in the compressed state, a diameter of 2 mm.

A further advantageous embodiment of the invention can provide that respectively adjacent lamellae abut against each other to form a seal along a longitudinal side which extends at least partially radially relative to the rotor axis.

While it is conceivable that the lamellae leave intermediate spaces between themselves, the efficiency of the fluid pump nevertheless increases with the seal of the blade formed by the lamellae. It is therefore advantageous if the lamellae abut against each other respectively on their longitudinal side and as far as possible leave no intermediate space there.

It can be provided in addition that respectively lamellae which are mutually directly adjacent abut against each other in such a manner that they are not pivotable relative to each other about the rotor axis in at least one direction. Hence, the individual lamellae can support each other mutually and, during operation, entirely withstand the counterpressure of the fluid to be pumped. In particular if the lamellae are distributed in a spiral on the circumference of the rotor shaft, support is provided in the azimuthal direction.

The invention can be designed in addition such that respectively adjacent lamellae mutually overlap in the region of the longitudinal side. As a result of overlapping of the lamellae, particularly high impermeability is produced and, in addition, the support function of the lamellae can be mutually exerted in the overlapping region.

Particularly high stability and impermeability between the lamellae is achieved by respectively adjacent lamellae engaging one in the other in the region of the longitudinal side. Any type of form-fitting design of adjacent lamellae can thereby be provided, for example respectively the provision of a fold along the longitudinal sides of the lamellae, for example also in the form of a thin sealing lip.

In order to produce a form-fitting and sealed connection, it can also be provided that at least one lamella, in particular all the lamellae, have a convex shape, in cross-section, on one of the longitudinal sides thereof and a concave shape on the other longitudinal side. The corresponding convex or concave structure can, in cross-section, be round, elliptical or also configured as a groove or notch.

Advantageously, respectively adjacent lamellae can be connected to each other by a flexible element, in particular a strip or a membrane. The ability of the blade to be opened out is then produced in the manner of a fan, in the case of which broad, rigid support bars are connected to each other by narrow membranes or strips.

In order to stabilise the individual lamellae these can respectively have a stiffening structure in cross-section, which provides for example a web extending in the longitudinal direction. However, it can also be provided that, additionally or alternatively, the individual lamellae are configured to be hollow with a round or square cross-section.

Advantageously, the invention can be configured by a blade in which at least two lamellae are connected to each other by a burr-like connection. Such a burr-like connection consists of small hook-like elements on the one side and loop-like elements on the respectively other side, which can be configured advantageously to be microscopically small.

The invention can furthermore be designed advantageously in that the connection is detachable by applying a load on the blade in the axial direction of the rotor and/or by a relative movement of two adjacent lamellae along their respective longitudinal sides and in the longitudinal direction of the lamellae.

The longitudinal direction of the lamellae is thereby dictated by the direction in which the respective lamella extends away from the rotor shaft.

As a result of the described structure of a blade for the rotor of a fluid pump, said blade can be designed to be particularly stable and compressible in a defined manner, as a result of which in particular good compressibility and a small final diameter of the rotor can be achieved in the compressed form.

The invention is shown and subsequently described in the following in a drawing with reference to an embodiment.

There are thereby shown:

FIG. 1 schematically in a three-dimensional view, a rotor shaft and also a blade,

FIG. 2 schematically, a part of a blade with a plurality of lamellae,

FIG. 3 a rotor shaft in cross-section with a lamella in two positions,

FIG. 4 a rotor shaft in cross-section with two lamellae in respectively two positions,

FIG. 5 a view of a rotor shaft with four lamellae,

FIG. 6 a view of a rotor shaft with two configurations of lamellae,

FIG. 7 a view of a rotor shaft with two configurations of lamellae and also

FIG. 8 a schematic representation of a heart catheter pump with a rotor and blades in a ventricle,

FIGS. 9 to 12 show schematic 3-dimensional illustrations of overlapping lamellae.

FIG. 1 shows a rotor shaft 1 having a blade 2 which is composed of individual, schematically indicated lamellae 3, 4, 5. The individual lamellae are mounted pivotably respectively by their feet 3 a, 4 a, 5 a on the rotor shaft 1, the feet of the lamellae together extending around the rotor shaft 1 in a spiral.

In this way, a helical structure of a blade is produced, which effects an axial conveyance of a liquid in the direction of the arrow 6 during rotation about the rotor shaft 1.

The particular embodiment of the blade according to the invention emerges in more detail from FIG. 2. In a first position, the lamellae 3, 4, 5 are represented there in the deployed, expanded shape of the blade, the adjacent lamellae abutting closely against each other by their longitudinal sides and hence forming a surface which is smooth and sealed for the flowing fluid.

In the position which is illustrated in broken lines and designated with 7, the individual lamellae are folded onto the rotor shaft 1 to an extent, it being important for the deformability of the complete blade that the individual lamellae 3, 4, 5 are moveable relative to each other, in particular are displaceable in the longitudinal direction. Consequently, folding of the corresponding surface is unnecessary but the individual lamellae can be folded quite far towards the rotor shaft, as is represented in the further position 8 of the lamellae.

As a result, the blade can be extensively compressed, i.e. can be reduced with respect to the radius, relative to the rotor shaft 1 or the longitudinal axis 1 a thereof.

No noteworthy elastic counterforces are thereby produced either so that the rotor can be compressed practically without force if this is required for example for introduction or removal of a corresponding fluid pump from a naturally occurring body vessel.

In FIG. 2, although pivotability of the individual lamellae in the longitudinal direction of the rotor shaft 1 in the plane of the rotor shaft axis is indicated, the invention is not however restricted hereto. FIG. 3 shows pivotability of a lamella 3 in the azimuthal direction, as indicated by the arrow 9.

FIG. 4 shows a further variant of such an embodiment, webs 10, 11 being provided on the rotor shaft and the lamellae 3, 4 being mounted pivotably on the webs 10, 11 which extend around the rotor shaft 1 in a spiral. The pivoted positions are represented respectively in broken lines in FIG. 4.

It becomes clear that the pivoting of the lamellae in the position illustrated respectively in broken lines leads to compression of the rotor. For example, compression of the rotor can be caused by a rotational operation of the rotor in a direction opposite to the operating direction. The deployment of the rotor takes place correspondingly by rotation in the operating direction.

Basically, the individual lamellae can also be mounted on transverse spars of the rotor shaft 1 and extend in the deployed state parallel to the longitudinal axis of the rotor shaft. It is important that they can be collapsed correspondingly individually in order to reduce the diameter of the rotor.

In FIG. 5, a plan view on four lamellae 12, 13, 14, 15 is shown schematically, said lamellae having respectively, in cross-section, a rectangular and hollow configuration in order to produce greater longitudinal rigidity of the individual lamellae. The objective therein is that, despite the rigidity of the individual lamellae, the blade in total can be collapsed easily.

FIG. 6 shows two configurations of lamellae, on the left side respectively lamellae 16, 17 which have an overlapping lip 18, 19 being illustrated, adjacent lamellae respectively forming a seal, on the one hand, and being supported, on the other hand on the overlapping lip 18, 19 of the adjacent lamella. As a result, rigidity of the blade in total is produced so that the blade withstands an increased fluid counterpressure during operation.

On the right side of FIG. 6, three lamellae 20, 21, 22 are illustrated, each of the lamellae having a web 20 a, 21 a, 22 a extending in the radial direction of the rotor shaft 1.

FIG. 7 shows, on left side of the plan view on the rotor shaft 1, three lamellae 23, 24, 25 which have, on one side 26, a convex protuberance and, on the other side 27, a concave recess in order that adjacent lamellae can engage one in the other and thus be mutually supported relative to an azimuthal pivoting position.

Lamellae 28, 29 are illustrated on the right side of FIG. 7, each of the lamellae having, on their longitudinal sides, a concave and a convex protuberance with a round cross-section. This design has the advantage that adjacent lamellae are rotatable about their longitudinal axis in a mutually restricted manner.

Basically, the individual lamellae can be mounted on the rotor shaft 1 either by means of a pivoting articulation or have a bendable or flexible configuration in their foot region such that they are pivotable in any case as a whole relative to the rotor shaft. The individual lamellae can also be glued by their foot ends respectively individually on a flexible strip or can be mounted on the latter in a different way, the strip with the lamellae being able as a whole to be mounted on the rotor. As a result of the flexibility of the strip, the pivotability of the individual lamellae can then be ensured.

In FIG. 8, the use of a fluid pump with a blade according to the invention is represented schematically, the pump 30 being positioned in a ventricle 31 and, as indicated by the arrows 32, sucks in blood which is conveyed into a vessel 33, as is shown by the arrows 34. The pump 30 is mounted on a catheter 35, which a shaft 1 illustrated only in the region of the pump 30 extends centrally and is actuated rotationally by means of a motor 36. The shaft moves a rotor 37 which has a blade, illustrated merely schematically.

The pump 30 in the expanded state has a diameter which can be possibly also be greater, in the extreme case, than the inner diameter of the vessel 33. For this purpose, the impeller is expanded fully. However, it can also be compressed in order to introduce or remove the pump 30, the individual lamellae, as illustrated above, being able to be folded against the rotor shaft 1 and, at the same time, the housing of the pump 30 being correspondingly collapsed. For this purpose, this housing can for example consist of a membrane which is deployed by a frame or by the fluid pressure produced in the pump 30.

FIG. 9 shows three flat lamellae which overlap at their longitudinal sides and can have for example a burr-like connection in their overlapping region.

FIG. 10 shows lamellae which have edges angled by 90 degrees along their longitudinal sides respectively and with which they hook one into the other, whilst a variant, in FIG. 11, is illustrated with an angle of less than 90 degrees which likewise allows fixing of the lamellae relative to each other.

FIG. 12 finally represents a variant with a curved edge which serves for the same purpose of mutual fixing. 

1-26. (canceled)
 27. A compressible and expandable blade for the rotor of a fluid pump, comprising: at least two lamellae which are disposed adjacently, are pivotable respectively relative to an axis of rotation of the rotor and moveable relative to each other, and abut against each other in the expanded state such that they form together a continuous blade surface.
 28. The blade according to claim 27, wherein at least two lamellae, in particular each of the lamellae, have a dimensionally stable, rigid configuration.
 29. The blade according to claim 28, wherein respectively adjacent lamellae abut against each other to form a seal along a longitudinal side which extends at least partially radially relative to the rotor axis of rotation.
 30. The blade according to claim 29, wherein respectively adjacent lamellae which are mutually directly adjacent abut against each other in such a manner that they are not pivotable relative to each other about the rotor axis of rotation in at least one direction.
 31. The blade according to claim 30, wherein respectively adjacent lamellae mutually overlap in the region of the longitudinal side.
 32. The blade according to claim 30, wherein respectively adjacent lamellae engage one in the other in the region of the longitudinal side.
 33. The blade according to claim 27, wherein respectively adjacent lamellae are connected to each other by a flexible element, in particular a strip or a membrane.
 34. The blade according to claim 27, wherein at least one of the lamellae has a stiffening structure in cross-section.
 35. The blade according to claim 34, wherein at least one lamellae, on its outer side, has at least one stiffening web extending in its longitudinal direction.
 36. The blade according to claim 34, wherein at least one lamellae has a hollow configuration in cross-section.
 37. The blade according to claim 36, wherein at least one lamellae has a convex shape, in cross-section, on one of the longitudinal sides thereof and a concave shape on the other longitudinal side.
 38. The blade according to claim 27, wherein at least two lamellae are connected to each other by a burr-like connection.
 39. The blade according to claim 38, wherein the connection is detachable by applying a load on the blade in the axial direction of the rotor.
 40. The blade according to claim 38, wherein the connection is detachable by the relative movement of two adjacent lamellae along their respective longitudinal sides and in the longitudinal direction of the lamellae.
 41. The blade according to claim 38, wherein the at least two adjacently-disposed lamellae belong to different rotor segments, one rotor segment comprising at least one lamella and also one hub segment.
 42. The blade according to claim 41, wherein the at least one lamella and also the hub segment of the rotor segment are in one part.
 43. The blade according to clam 42, wherein respectively two adjacently-situated rotor segments are connected to each other non-rotatably in a form fit.
 44. The blade according to claim 43, wherein one rotor segment has one, two or more lamellae.
 45. The blade according to claim 40, wherein rotor segments with connection webs disposed between the hub segments can be worked out of a flat material and can be disposed on a rotor shaft by folding the flat material out of the surface plane in such a manner that a helix shape of the blade is produced.
 46. The blade according to claim 40, wherein a plurality of lamellae are part of one lamella body, these being connected to each other only in their foot region.
 47. The blade according to claim 45, wherein the lamella basic body can be introduced into a hub body such that, in the unloaded state of the radially outer tips of the lamellae, a helix shape of the blade is formed.
 48. The blade according to claim 47, wherein the lamellae are respectively coated and/or covered with a membrane, a connection of the coating/membrane of two adjacent lamellae being frictional and/or form-locking.
 49. The blade according to claim 48, wherein, on the flow pressure side, the proximal region of the distal lamella covers the distal region of the proximal lamella.
 50. The blade according to claim 49, wherein application of the lamellae in a compressed state is possible essentially in a serial manner, beginning with the most proximal lamella.
 51. A catheter pump for introduction into human vessels, in particular for intraventricular use, comprising a rotor with a blade being able to be disposed in a mammalien vessel, wherein the pump has a conveying direction for conveying body fluid and the blade hereby has a flow pressure side and a flow suction side and also comprises a blade.
 52. A method for the production of a blade, comprising: structures for hub segments and also lamellae cut out from a basic body, a connection web between said hub segments and said lamellae remaining, at least the lamellae being plastically deformed in a radially protruding state and/or being heat-treated, then the rotor segments being jointed axially to form a rotor shaft.
 53. The method of claim 52, wherein said structures for hub segments and lamellae are cut out by a laser.
 54. The method of claim 52, wherein said structures for hub segments and lamellae are cut out by wire eroding.
 55. The method of claim 52, wherein said basic body is tubular.
 56. The method of claim 52, further comprising surface treating the lamellae.
 57. The method of claim 52, further comprising fixing the rotor segments by welding.
 58. The method of claim 57, wherein the welding is laser welding. 